Method of manufacturing steel sheets



. tion.

Patented May 5, 1925.

WILLIAM E. CAUGHERTY AND SAMUEL C. HOCKEY, F NATRONA, PENNSYLVANIA.

METHOD OF MANUFACTURING STEEL SHEETS.

No Drawing.

To all whom it may'concem:

Be it known that we, WILLIAM E. CAUGHERTY and SAMUEL C. HOOKEY, citi-Zens of the United States, and residents, re spectively, of Natrona andNatrona, in the county of Allegheny and .State of Pennsylvania, havemade a new and useful Invention in Methods of Manufacturing SteelSheets, of which the following is a specificzu This invention relates tothe manufacture of high-grade steel sheets such as required inthe'automobile, metal furniture and other trades where highly finishedsurfaces are necessary and where the sheets must be sufficiently ductileto permit of deep drawing and stamping operations.

In an application filed by Otto H. C-unningham on October 8th, 1924, hediscloses a method of manufacturing such sheets, and one of the objectsof this invention is to improve and cheapen the method disclosed in saidapplication.

A further object of this invention is to provide a method ofmanufacturing such sheets with the regular sheet mill equipment, butusing less men, whereby a material increase in tonnage per man hour isobtained over that possible in standard sheet mill practice as well asover that with the method disclosed in said Cunningham application.

Under the present standard practice of manufacturing high-grade stampingand drawing sheets from relatively low carbon steel, in order to producea 20-gauge sheet X 96", the sheet bars are heated and broken down toabout sixty per cent of the finished length required in the sheets.These breakdowns are then pickled, matched in packs, reheated andfinished to the length required.

As there is very little additional work to be done on these sheets inthe subsequent operations, it is necessary to have a highgihde surfaceon the sheets as they leave the hot mills. This necessitates extremelysmooth rolls and also requires that the sheet bars are not heated up tofree scaling temper-ature. These factors all contribute to retardproduction and increase the difficulties of rolling,

Under the standard practice, it is customary to use a crew of ten men.

. ;ln carrying out our method in producing 20-gauge sheets 80 x 96', thesheet bars are Application filed October 13, 1924. Serial 110,143,499.

heated to a relatively high temperature and broken down to within fromsixty per cent to seventy-five per cent of the length of the finishedsheets.

The breakdowns are then annealed or normalized at a temperature whichranges from 1600 to 17 00 F. The normalized sheets are then pickled toremove the scale, cold rolled to length, and annealed by standard boxannealing methods at a temperature sufficiently low to prevent stickingor welding.

We have discovered that, in order to obtain the necessary reduction bycold rolling (ranging from 25% to 40%), it is necessary to use oil onthe rolls. Mineral oil is preferable and this is preferably sprayed ontothe rolls during the rolling operation.

Because of the fact that all surface defects are eliminated by the coldrolling operation, we find that it is unnecessary to exercise the samecare in heating and break-- ing down the sheet bars as in standard sheetmill practice.

In practicing our method, we are able to heat the sheet bars and thepacks'more rapidly and to roll them with heavier drafts and faster thanis customary in standard practice, and we find that we are able to dothis with seven men instead of ten as is now customary. These factorsenable us to produce a tonnage that is at least twice as great as thetonnage produced by standard practice.

By means of this method, we are enabled to produce sheets of uniformlyhigh-grade surface; sheets that are much more accurate as to gauge thanthose obtained by the standard sheet mill me hods of production, andsheets that are free from Steads brittleness and, therefore, suitablefor deep drawing and stamping operations.

Having thus described our invention, what we claim is 1. The method ofmaking highly finished steel sheets free from Steads brittleness, whichconsists in heating the sheetbars to a relatively high temperature, thenin rolling said bars to less than 75 per cent of the length of thesheets to be produced, then in annealing and pickling the semi-finishedsheets, then in cold rolling the semi-finished sheets to length and thenin annealing the sheets.

2. The method of making highly finished steel sheets free from St-eadsbrittleness, which consists in heating the sheet bars to a relativelyhigh temperature, then in rolling said bars to between '60 per cent and7 5 per cent of the length of the sheets to be produced, then inannealing and ickling the semi-finished sheets, then in col rolling thesemi-finished sheets to length and then in annealing the sheets.

3. The method of making highly finished steel sheets free from Steadsbrittleness, which consists in heating the sheet bars to a relativelyhigh temperature, then in rolling said bars to 60 per cent of the lengthof the sheets to be produced, then in annealing and pickling thesemi-finished sheets, then in cold rolling the semi-finished sheets tolength and then in annealing the sheets.

4. The method of making highly finished steel sheets free from Steadsbrittleness, which consists in quickly heating sheet bars to arelatively high temperature, then in quickly rolling said bars to lessthan 7 5 per cent of the length of the sheets to be produced then inannealing and pickling the seminished sheets, then in cold rolling thesemi-finished sheets to length and then in box annealing the sheets at atemperature below Welding temperature.

5. The method of making highly finished steel sheets free from Steadsbrittleness, Which consists in heating the sheet bars to a relativelyhigh temperature, then in rolling said bars to approximately 75 per centof the length of the sheets to be produced, then in annealing andpickling the semi-finished sheets, then in cold rolling the same tolength and then in annealing the sheets.

6. The method of making highly finished steel sheets free from Steadsbrittleness, which consists in heating sheet bars to a relatively hightemperature, then in rolling said bars to approximately 75 per cent ofthe length of the sheets -to be produced, then in annealing ornormalizing the semi-linished sheets, then in cold rolling thesemifinished sheets to length and gauge and then in annealing the same,

In testimony whereof, We have hereunto set our names this 8th day ofOctober, 192-1.

\VILLIAM E. CAUGHERTY. SAMUEL C. HOOKEY.

